Most efficent heating type

[Nick Coffelt]

Good morning,

Curious what others have for heating in thier shops. Mine is a detached shop and I'd like to be able to keep it 40-45 degree when not using it (in the winter). In Iowa temps can dip to subzero.

Been thinking of adding in a Reznor or other style propane shop heater, I'm just concerned that while trying to keep it 45 degrees I'll burn through 500 gallons of propane.

Any suggestions?

24' x 32' shop, 9' side walls with 20' peak. Insulated on all walls and ceiling. There is a loft (hence the tall center height).

Thanks,

[roger wiegand]

Controlling air infiltration and adding insulation are the keys to energy efficiency. Get your ceiling up to R60, walls to R30 or better, caulk or foam every penetration, sill plates, window cavities etc. Add storm windows or upgrade the windows only if they are pretty bad. Then for minimal fuel use you can use pretty much any 90+ AFUE furnace. You can pay the big bucks to go from 90 to 97, but a small fraction of that money put into additional insulation and sealing will have a much bigger payback.

For my 34x36 2-story barn in MA (so also some subzero days) it costs me between $40 and $60 a month for gas, keeping it at 45 most of the week and 62 on the weekends. I use a small Modine direct vent heater that hangs on the ceiling, it is only an 80% efficient heater. Because of the condition of the building and the issues of trying to vent the hip roof I opted for spray foam insulation throughout, which gave me both excellent air sealing and insulation. My windows are very low end, but I haven't seen the logic for investing probably $15-20K to upgrade them.

[Steve Rozmiarek]

I don't know what the most efficient is, but I have been around forced air propane furnace, overhead radiant, oil burning and woodburning stoves, and electrical. They all have pros and cons. If you want easy, it costs a little more. You can heat for cheap if you don't count the costs associated with cutting your own firewood for example. Much easier to call the propane truck. IMHO, actual costs are very similar. I personally would go with whatever matches the pros list you need. I like forced air best, radiant is ok, especially in floor.

[Jerome Stanek]

I have an unvented wall heater in my shop 99% efficent.

[Nick Coffelt]

While this building was an old barn, I've gone through and insulated and sealed every crack I can find. For the floor I opted for a "floating" floor of sorts, where I've spanned 2/10's the length of the shop with 1 1/2" insulation between joists which are above a sealed crawl space. All the floors have a minimum of 1 1/2" thick insulation board, walls are a miture of blow in insulation where I had good seal and spray where there were some gaps (cost effective). Windows are all high efficiency.

Only real issue is that I have a sliding door which I have insulated and add rubber gasket around the perimeter.

Sounds like my suspicions are coming to truth, that it really doesnt matter. I'd prefer propane as I have regular propane service.

[Jerome Stanek]

Mine is propane

[Pat Barry]

You should consider installing some fans to get the warm air back down from the high ceiling. That will maximize your heating efficiency and comfort level

[Jim Andrew]

I got a used high efficiency propane furnace for my shop, and 2 years ago had my old AC from the house added to the shop. I also have a wood furnace, and use it to heat above 45. That way I can burn all my scraps. Also have so much wood from the farm, that it is impossible to burn enough to keep it under control. Insulation is really the key to a comfortable affordable shop. Only have to buy the insulation once.

[Larry Edgerton]

. Also have so much wood from the farm, that it is impossible to burn enough to keep it under control. Insulation is really the key to a comfortable affordable shop. Only have to buy the insulation once.

What he said......

Ceiling fans are good, but keep in mind that the root problem of high temps at the ceiling is cold air coming in, settling on the floor and pushing the hot air up. Cutting drafts to an absolute minimum will greatly change the high/low temperature differential to one more acceptable. You can push the air down, but there is still cold air coming in. My house has 11' ceilings, and the floor to ceiling differential is less than two degrees, but the house is extremely tight.

Infiltration costs more money in heat loss than insulation losses. Keep your foam gun handy!

Larry

PS: I tried radient tube heat in a woodshop and although it was efficient it was not good in a woodshop. It cupped boards left under it within 20 minutes.

[Pat Barry]

I agree 100% on insulation and air infiltration as discussed numerous times previously. To be clear, even with all that, the high ceiling will be where the heat goes so you still need to keep it down near the floor where you are working. Otherwise the room will be 65 and the upper area will be 85. Where is the efficiency in that?

[Frank Pratt]

If you can have both the return air and supply air ducts at floor level it helps tremendously. Normally my shop is just a few degrees above freezing & I turn up the heat when I'm working in there. The floors are concrete but I never get cold feet.

[Bill George]

In a house you normally put the returns on the inside wall or hallway and supply air sweeping the outside walls. Both low in Iowa or a heating more than cooling part of the country anyway. In a shop, or in mine anyway I have a hanging heater blowing warm air low and toward the overhead (insulated) door area. R-13 in the ceilings and walls. Keep it at 45 except when working. The very cold sub-zero days, I stay in the house.
On a propane heat system, I'd insulate what I could. Use the heater to hold at 45 and then use wood heat to bring it up to a nice warm temperature. If you have tall ceilings, put in a ceiling fan as suggested. Warm air naturally rises so in a tall ceiling room that's where its at.

[Martin Wasner]

My shop is heated with an off peak boiler. Costs about $100 per month to heat 2500 square feet. I'm in Minnesota.

[Henry Kramer]

My detached shop is about the same size as yours Nick. I installed a natural gas furnace in the attic with four drops. I have 8' ceiling and the walls are brick outside block inside with an air cavity along with 1 inch of foam (9" wall). I have a wide range thermostat that I can turn down to 35 degrees when I'm not there but even on the coldest days in Chicago it never goes below 40 degrees and doesn't cost that must to heat.

[Larry Edgerton]

Henry, the hanging box heaters are not the most efficient, but they are easy. I have a Sterling OV2 200,000 btu in my barn. The nice thing about a Sterling over a Reznor is that the sterling is a direct power vent and can be vented through the wall. No worries about leaks on a steel roof, or any roof really.

Larry

[Mark Blatter]

You should consider installing some fans to get the warm air back down from the high ceiling. That will maximize your heating efficiency and comfort level

When I was a kid oh so many years ago, I used to go to a local service station with my dad. He and the owner were good friends, plus this was back when a service station was just that. They had four stalls to work on cars, plus sold gas. The owner had a clear tube of soft plastic with a fan on the top end and just the opening on the bottom. It was attached so the top was right at the top of the inside of the building and extended down to about 3' from the floor. All it did was take the hot air from the peak and blow it down to the floor. I am sure it cost almost nothing to run and gave lots of pretty warm air where they really needed it. This was in Great Falls, MT so, yeah, we had a bit of cold weather now and again.

I have looked for something like this and have not been able to find anything. The closest I can come are the advertising tubes with the fans where the tube is a guy and he inflates, then partially deflates, then inflates......

Just a simple plastic tube of perhaps 6 mil walls so it could be rolled up and stored away in summer, with a fan on the end.

[Rod Sheridan]

Nick, the most efficient type of heater is the electric heater as 100% of the energy input heats the building.

Unfortunately it's often the most expensive type to operate.

Any local HVAC company can have a look at your shop, determine the losses, what size of heater you'll need and the lowest operating cost choice.

Regards, Rod.

[Wade Lippman]

5 years ago I compared electric to propane and found they were about the same. I'd bet electric is even cheaper now. But of course your area might be different.

[Mike Cutler]

Nick

The most efficiency gains will be realized by proper insulation. Everyone is correct on this. I think Iowa is known for getting pretty cold in the winter, and hot in the summer.;)
Electric heaters, as Rod pointed out, are technically the most efficient heat devices you can use, but they're also the most costly to operate depending on your location.
I think the most efficient propane heater run in the mid 80 percent range and #2 fuel oil furnaces can be in the low to mid 90's. There are some more efficient propane systems, but very costly to install.
If you have Natural Gas to your house that would be my very first choice.

[Dennis Aspö]

I use an electric heater, my shop is well insulated though there are improvements that could be made, and I have to keep ventilation going anyway. I was able to cease using the heater a month ago here in Finland and the temperature in the shop keeps around 10C or 66F, and it's also noticeably colder than the outside a lot of the time too. For additional heat I am building a south wall facing solar collector that will circulate the air through it for additional heating in autumns and spring.

[Mike Kees]

As a contractor who has seen all kinds of heat systems I have come to the conclusion that insulation and vapour barrier (poly) are at least as important or more important to efficient heating than the actual heating choice. Natural gas , electric etc. I live in Alberta and so in my own shop I installed rigid foam under my concrete floor, my foundation is ICF 4FEETHIGH






Sorry guys... Anyhow the walls are r-28 and my cieling is R-50. I heat with two overhead radiant natural gas heaters. It works really well and costs about 50 to 60 dollars to heat. natural gas is the heat source of choice in Alberta so I would only probally have the option of wood as a second choice.

[paul cottingham]

Heat pump.

[Steve Rozmiarek]

Heat pump.

Having lived with three different ground source heat pumps in the last ten years, it has become blatantly obvious to me that regardless how efficient they are in my area, they cost more to install and run because of the cost of electricity, so they are a terrible false economy.